The present invention relates to acoustic sensors and, more particularly, wearable physiological acoustic sensors.
Physiological acoustic sensors gather physiological sounds from the human body that can be applied to a variety of health diagnostic purposes. For example, heart and lung sounds can be used to estimate vital sign values, such as heart rate and respiration rate. Heart and lung sounds can also be used to detect a host of health problems. For example, heart sounds can be used to identify heart anomalies, such as presence of the S3, S4 sounds, splits of the Si and S2 sounds, rubs, click and heart murmurs that indicate mitral or aortic regurgitation, mitral or aortic stenosis or patent ductos arteriosus. Lung sounds can be used to identify breathing anomalies, such as wheeze, stridor, grasp, rales and crackles. Additionally, physiological acoustic sensors can detect other organ sounds of interest, such as sounds indicating the start of digestive cycles that can be used to set optimal feeding schedules for comatose patients.
Some physiological acoustic sensors, such as electronic stethoscopes, gather physiological sounds in episodic spot checks. These sensors are not wearable by the person being monitored and do not provide continuous, real-time monitoring of vital sign values or health diagnostics.
Other physiological acoustic sensors are mounted on the body or worn on clothing of the person being monitored. While conventional wearable sensors can provide continuous, real-time monitoring, they are often highly susceptible to impulse noise from abrupt hits, clothing scrapes and other motion-related events as well as background noise from the surrounding environment. Moreover, these conventional sensors often have a large form factor which does not keep close enough proximity between the body microphone and the body of patients to provide good body sound capture, subjects patients to discomfort and provides an intrusive presence.